It's barely bigger than a cell phone. The screen is too small to comfortably use for browsing without zooming etc (like a cell phone), and the device is too large to carry around easily. It's a squint-o-matic .
I think that angle and the way he is holding it makes it appear smaller than it really is. Here is a 7" Galaxy Tablet next to a phone with a 4" screen.
My gf has that older Galaxy 7" tablet, and while it's too small for me, she mostly reads books on it, and it's the perfect size for that. Also much easier to type on it in portrait mode.
Looking at the video - non-geeks are going to love that interface. Moreover by positioning it as purely a consumption device, they complete side-step the multi-tasking issue that people like us obsess over.